I have come to my own conclusions on Oceanic ...

Not a good choice for new tanks - Out of the bucket, Ca is too high and Alk & PH are too low. I setup my system using Oceanic and struggled to balance out everything. Now that my tanks are approaching a year runing (has it been that long?), I am still using Oceanic but the system seems to be reaching a maturity level that's keeping things much more stable. Ca 350-400, dKH 10, PH 8.1. A 15-20% water change with Oceanic has no noticable impact on PH or dKH, and the Ca gets a little boost (maybe 25ppm).

So, I like Oceanic for an established tank, and really like the way it dissolves, but would probably start a new tank with something else next time.